Nucleotide sequence of the Shiga-like toxin genes of Escherichia coli.
AUTOR(ES)
Calderwood, S B
RESUMO
We have determined the nucleotide sequence of the sltA and sltB genes that encode the Shiga-like toxin (SLT) produced by Escherichia coli phage H19B. The amino acid composition of the A and B subunits of SLT is very similar to that previously established for Shiga toxin from Shigella dysenteriae 1, and the deduced amino acid sequence of the B subunit of SLT is identical with that reported for the B subunit of Shiga toxin. The genes for the A and B subunits of SLT apparently constitute an operon, with only 12 nucleotides separating the coding regions. There is a 21-base-pair region of dyad symmetry overlapping the proposed promoter of the slt operon that may be involved in regulation of SLT production by iron. The peptide sequence of the A subunit of SLT is homologous to the A subunit of the plant toxin ricin, providing evidence for the hypothesis that certain prokaryotic toxins may be evolutionarily related to eukaryotic enzymes.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=305089Documentos Relacionados
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